The present invention relates to a direct contact thermal interface for demountably interconnecting a multistage cryocooler and a magnetic resonance magnet.
Cryocoolers using the Gifford-McMahon cycle, for example, can achieve low temperatures at their heat stations for removing heat from the interior of superconducting magnets. The heat stations in a two stage cryocooler are located at the end of the first and second stages of the cold head portion of the cryocooler. To connect the cryocooler heat stations to surfaces, such as radiation shields, from which heat is to be removed, high contact forces are needed as well as soft metal interfaces in order to achieve low thermal resistances. Since the cryocooler is removable, heavy frost can accumulate at the interface when the cryocooler is removed for servicing. Re-establishing the connection in the presence of heavy frost can be difficult.
Differential expansion or contraction between a two stage cryocooler and the interface receptacle can also interfere with the formation of thermally efficient contact resistances.
It is an object of the present invention to provide a cryocooler cold head interface receptacle for making reliable contacts with low thermal resistance at cryogenic temperatures.
It is another object of the present invention to independently control contact forces at each stage of the cryocooler cold head.